/in/foo.c: In function 'main':
/in/foo.c:10:4: warning: iteration 4 invokes undefined behavior [-Waggressive-loop-optimizations]
  { printf("%-8d",f[i]);
    ^~~~~~~~~~~~~~~~~~~
/in/foo.c:9:2: note: within this loop
  for(i=1;i<=m;i++)
  ^~~
/in/foo.c:8:7: warning: iteration 2 invokes undefined behavior [-Waggressive-loop-optimizations]
   f[i]=f[i-1]+f[i-2];
   ~~~~^~~~~~~~~~~~~~
/in/foo.c:7:2: note: within this loop
  for(i=3;i<=m;i++)
  ^~~
/in/foo.c:8:4: warning: array subscript is above array bounds [-Warray-bounds]
   f[i]=f[i-1]+f[i-2];
   ~^~~